// Run like this:  simple_client address port
// Results in argv ["./simple_client", "address", "port"]

#include<sys/socket.h>
#include<sys/types.h>
#include<netinet/ip.h>
#include<netdb.h>
#include<arpa/inet.h>
#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<time.h>
#include<signal.h>
#include<string.h>

#define bufsize 4096

void handle_sigpipe(int signal){
	printf("Sigpipe received, continuing\n");
}

int main(int argc, char ** argv){
	struct sigaction pipe_handler;
	pipe_handler.sa_handler = handle_sigpipe;
	sigaction(SIGPIPE, &pipe_handler, 0);

	if(argc < 3){
		printf("Usage:  %s hostname port [-c] \n", argv[0]);
		printf("Setting -c will send a valid but strange character followed by fuzz\n");
		return 1;
	}
	char send_character = 0;
	if(argc == 4){
		for(int i = 1; i < argc; i++){
			if(!strcmp(argv[i], "-c"))
				send_character = 1;
		}
	}	

	struct sockaddr_in sad;
	sad.sin_port = htons(atoi(argv[2]));
	sad.sin_family = AF_INET;

	// do a dns lookup
	struct hostent* entry = gethostbyname(argv[1]);
	if(!entry){
		if(h_errno == HOST_NOT_FOUND){
			printf("This is our own message that says the host wasn't found\n");
		}
		herror("gethostbyname");
		return 1;
	}
	struct in_addr **addr_list = (struct in_addr**)entry->h_addr_list;  // -> is like (*entry).h_addr_list
	struct in_addr* c_addr = addr_list[0];
	char* ip_string = inet_ntoa(*c_addr);
	sad.sin_addr = *c_addr; // copy the address we found into sad
	// Finally done with DNS!
	printf("Connecting to:  %s\n", ip_string);

	// seed first
	srandom(time(0));
	size_t writelen;
	int random_numbers[bufsize / sizeof(int)];
	while(1){
		int skt = socket(AF_INET, SOCK_STREAM, 0);

		if( connect(skt, (struct sockaddr*)&sad, sizeof(struct sockaddr_in)) ){
			perror("connect");
			return 1;
		}
		if(send_character){
			printf("Sending a valid but strange character followed by fuzz\n");
			uint8_t character_buffer[48];
			for(int i = 0; i < 48; i++)
				character_buffer[i] = random() % 255;
			character_buffer[0] = 10;
			memset(character_buffer + 34, 0, 6);
			write(skt, character_buffer, 48);
			uint16_t description_length;
			memcpy(&description_length, character_buffer + 46, 2);
			uint8_t random_byte;
			for(int i = 0; i < description_length; i++){
				random_byte = random() % 255;
				write(skt, &random_byte, 1);
			}
			random_byte = 6;
			write(skt, &random_byte, 1);
		} else
			printf("Sending Fuzz\n");
		do {
			for(int i = 0; i < bufsize / sizeof(int); i++)
				random_numbers[i] = random();
			writelen = 1 + random() % (bufsize - 1);
		} while (write(skt, random_numbers, writelen) == writelen);
		close(skt);
	}

	return 0;
}